In 1992 Hogwarts became under threat from the re-opened Chamber of Secrets and the basilisk it contained inside and as a precaution, students were taught how to duel. Millicent and Hermione Granger were paired together during the short-lived Duelling Club. Their duel spiralled into a physical brawl, with Millicent holding Hermione in a headlock, in spite of the standard "no contact" rule in duelling.

Hermione's friend, Harry Potter, came to her rescue, breaking the two girls up. Hermione later used hair from this incident to try to assume Millicent's form with Polyjuice Potion, as the real Millicent went home for Christmas. However, the hair she obtained turned out to be that of Millicent's cat and her transformation unintentionally took the place of her cat, resulting in Hermione spending some time in the Hospital Wing.[4]

Fifth year

"The Inquisitorial Squad, Granger. A select group of students who are supportive of the Ministry of Magic, hand-picked by Professor Umbridge. Anyway, members of the Inquisitorial Squad do have the power to dock points... New Head, new times..."

Sixth year

Millicent at Hogwarts.

In Millicent's sixth year she had lost her former power of being in the Inquisitorial Squad and could no longer use it to her advantage. Her friend, Draco Malfoy had joined the Death Eaters and put strain on his friendships. Severus Snape, her head of house, had now taken on the position of Defence Against the Dark Arts teacher and favoured Slytherins during his lessons. Later on in this year, headmaster Albus Dumbledore was killed.

Seventh year

Due to her presumed pure-blood status and Slytherin relations, it is assumed that Millicent was allowed to return to Hogwarts in 1997 when it was under the control of Lord Voldemort, with her former head of house Severus Snape acting as headmaster. If she did, Millicent would have been present for the evacuation of Hogwarts preceding the Battle of Hogwarts, and it would be assumed that Millicent left the castle along with the other members of the House of Slytherin, rather than choosing to fight Voldemort's army. It could also be a possibility that Millicent would return to Hogwarts, fighting against the school alongside Death Eaters, as did some other students of Slytherin.

Physical appearance

Millicent was black-haired and had a heavy, jutting jaw. She was described by Harry Potter as being "no pixie." She had a large, square build that allowed her to physically intimidate smaller people, and was bigger than Harry Potter in their second year. Ron Weasley once remarked that Millicent was "ugly," and Harry thought that she looked like a hag he'd seen pictured in Holidays with Hags. We are given no non-Gryffindor opinions of her physical beauty or lack thereof.[4]

Etymology

The name Millicent is Germanic, meaning "she with the gentle gait". This is ironic, considering that Millicent Bulstrode is not portrayed as gentle or graceful in the least; Harry Potter once remarked that she's "no pixie" while they were taking Polyjuice Potion, in relation to the fact that Millicent, Crabbe and Goyle would not fit into a single toilet cubicle.

Millicent may also come from the Latin words mille, meaning "thousand", and centum, meaning "hundred". It also sounds similar to the word "militant", which matches her aggressive personality.

Because her role appears to be such an obscure cameo that even the most sharp-eyed of fans would have trouble picking up on, it is also possible that her actual role was cut and that the presumed cameo of Millicent is simply that of an unnamed student.

In the books, Millicent's hair is black. In the Chamber of Secrets film, Millicent is portrayed by a brunette actress.

In the video game adaptation of Harry Potter and the Chamber of Secrets, there is a Slytherin girl, strongly hinted to be Millicent, who says her own distinct lines, such as finding Professor Snape more attractive than Professor Lockhart. She is also mentioned by other female students as being "a real witch", and she leaves Harry many a snarky remark.